Minimizing block error rate (BLER) associated with a beam switch

ABSTRACT

Aspects of the disclosure relate to minimizing the block error rate (BLER) experienced by a user equipment (UE) upon a downlink beam switch at the base station. The base station may mitigate the link adaptation convergence transient upon performing a beam switch by modifying the modulation and coding scheme (MCS) according to a difference in reference signal received power (RSRP) between the old beam and the new beam. The base station may further adjust the MCS utilizing an outer-loop link adaptation process or channel state feedback (CSF) provided by the UE after the beam switch. Other aspects, features, and embodiments are also claimed and described.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is related to concurrently filed, co-pendingU.S. Non-Provisional application Ser. No. 16/528,451, filed on the sameday as this application, which is incorporated herein by reference as iffully set forth below.

TECHNICAL FIELD

The technology discussed below relates generally to wirelesscommunication networks, and more particularly, to adjusting transmissionand reception characteristics associated with a beam switch (e.g., aftera beam switch) in beam-based communication scenarios (e.g., milli-meterwave beams). Some embodiments and techniques enable and providecommunication devices, methods, and systems with techniques forminimizing block error rate (sometimes abbreviated as BLER) associatedwith performing a beam switch (e.g. before, during, or after a beamswitch).

INTRODUCTION

In wireless communication systems, such as those specified understandards for 5G New Radio (NR), a base station and user equipment (UE)may utilize beamforming to compensate for high path loss and shortrange. Beamforming is a signal processing technique used with an antennaarray for directional signal transmission and/or reception. Each antennain the antenna array transmits a signal that is combined with othersignals of other antennas of the same array in such a way that signalsat particular angles experience constructive interference while othersexperience destructive interference.

As the demand for mobile broadband access continues to increase,research and development continue to advance beamforming communicationtechnologies, including technologies for enhancing beamformingmanagement in particular, not only to meet the growing demand for mobilebroadband access, but to advance and enhance the user experience withmobile communications.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a summary of one or more aspects of the presentdisclosure, in order to provide a basic understanding of such aspects.This summary is not an extensive overview of all contemplated featuresof the disclosure and is intended neither to identify key or criticalelements of all aspects of the disclosure nor to delineate the scope ofany or all aspects of the disclosure. Its sole purpose is to presentsome concepts of one or more aspects of the disclosure in a form as aprelude to the more detailed description that is presented later.

Various aspects of the disclosure relate to minimizing block error rate(BLER) experienced by a user equipment (UE) in beam-based communicationscenarios. BLER can be minimized upon a downlink beam switch at a basestation. As one example, a base station may mitigate link adaptationconvergence transient issues upon performing a beam switch by modifyinga modulation and coding scheme (MCS). Modification can be done accordingto a difference in reference signal received power (RSRP) measurementsof various beams (e.g., between an existing or old beam and a new orexpected beam). The MCS modification may occur soon after after a beamswitch to minimize the BLER at the UE (e.g., in a first slot after abeam switch). In some examples, the base station may further adjust theMCS utilizing an outer-loop link adaptation process or channel statefeedback (CSF) provided by the UE after the beam switch. Disclosedaspects include a variety of method, system, device, and apparatusembodiments.

In one example, a method for wireless communication at a base station ina wireless communication network is disclosed. The method can includecommunicating with a user equipment (UE) utilizing a first downlink beamof a plurality of downlink beams and switching from the first downlinkbeam to a second downlink beam of the plurality of downlink beams tocommunicate with the UE. Switching can occur based on a difference inmeasured or observed power reference signal levels (e.g., between afirst reference signal received power (RSRP) associated with the firstdownlink beam and a second RSRP associated with the second downlinkbeam). The method may also include modifying a modulation and codingscheme (MCS) utilized for communication with the UE based on thedifference between the first RSRP and the second RSRP.

Another example provides a base station in a wireless communicationnetwork including a wireless transceiver, a memory, and a processorcommunicatively coupled to the wireless transceiver and the memory. Theprocessor can be configured to communicate with a user equipment (UE)utilizing a first downlink beam of a plurality of downlink beams andswitch from the first downlink beam to a second downlink beam of theplurality of downlink beams to communicate with the UE. Switching canoccur based on a difference in measured or observed power referencesignal levels (e.g., between a first reference signal received power(RSRP) associated with the first downlink beam and a second RSRPassociated with the second downlink beam). The processor can also beconfigured to modify a modulation and coding scheme (MCS) utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP.

Another example provides a base station in a wireless communicationnetwork.

The base station can include means for communicating with a userequipment (UE) utilizing a first downlink beam of a plurality ofdownlink beams and means for switching from the first downlink beam to asecond downlink beam of the plurality of downlink beams to communicatewith the UE. Switching can occur based on a difference in measured orobserved power reference signal levels (e.g., between a first referencesignal received power (RSRP) associated with the first downlink beam anda second RSRP associated with the second downlink beam). The basestation can also include means for modifying a modulation and codingscheme (MCS) utilized for communication with the UE based on thedifference between the first RSRP and the second RSRP.

Another example provides a non-transitory computer-readable mediumincluding code for causing a base station to communicate with a userequipment (UE) utilizing a first downlink beam of a plurality ofdownlink beams and switch from the first downlink beam to a seconddownlink beam of the plurality of downlink beams to communicate with theUE. Switching can occur based on a difference in measured or observedpower reference signal levels (e.g., between a first reference signalreceived power (RSRP) associated with the first downlink beam and asecond RSRP associated with the second downlink beam). Thenon-transitory computer-readable medium can also include code forcausing the base station to modify a modulation and coding scheme (MCS)utilized for communication with the UE based on the difference betweenthe first RSRP and the second RSRP.

Various method, system, device, and apparatus embodiments may alsoinclude additional features. For example, the first downlink beam andthe second downlink beam may have the same or different widths. Inaddition, the base station may communicate with the UE utilizing amillimeter wave carrier frequency.

In some examples, the base station may further be configured to receiveat least one beam measurement report the UE, where each of the firstRSRP and the second RSRP are included in one of the at least one beammeasurement report. The base station may further be configured tocalculate the difference between the first RSRP and the second RSRPbased on the beam measurement report. In other examples, the basestation may further be configured to estimate the difference between thefirst RSRP and the second RSRP based on respective signal qualitymeasurements of a first uplink beam corresponding to the first downlinkbeam and a second uplink beam corresponding to the second downlink beam.

In some examples, the base station may be configured to adjust the MCSutilizing an outer-loop link adaptation process. For example, the basestation may be configured to receive acknowledgement information fromthe UE and adjust the MCS based on the acknowledgement information. Inother examples, the base station may be configured to transmit a channelstate information-reference signal (CSI-RS) to the UE via the secondbeam, receive channel state feedback (CSF) from the UE, and adjust theMCS based on the CSF.

These and other aspects will become more fully understood upon a reviewof the detailed description, which follows. Other aspects, features, andembodiments will become apparent to those of ordinary skill in the art,upon reviewing the following description of specific, exemplaryembodiments of in conjunction with the accompanying figures. Whilefeatures may be discussed relative to certain embodiments and figuresbelow, all embodiments can include one or more of the advantageousfeatures discussed herein. In other words, while one or more embodimentsmay be discussed as having certain advantageous features, one or more ofsuch features may also be used in accordance with the variousembodiments discussed herein. In similar fashion, while exemplaryembodiments may be discussed below as device, system, or methodembodiments such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a wireless communication systemaccording to some aspects.

FIG. 2 is a conceptual illustration of an example of a radio accessnetwork according to some aspects.

FIG. 3 is a diagram illustrating an example of a frame structure for usein a radio access network according to some aspects.

FIG. 4 is a block diagram illustrating a wireless communication systemsupporting beamforming and/or multiple-input multiple-output (MIMO)communication according to some aspects.

FIG. 5 is a diagram illustrating an example of communication between abase station and a user equipment (UE) using beamforming according tosome aspects.

FIG. 6 is a block diagram illustrating exemplary components of a UEaccording to some aspects.

FIG. 7 is a signaling diagram illustrating exemplary signaling forminimizing the BLER based on an expected beam switch according to someaspects.

FIG. 8 is a block diagram illustrating an example of a hardwareimplementation for a UE employing a processing system according to someaspects.

FIG. 9 is a flow chart of an exemplary method for a UE to minimize BLERassociated with an expected beam switch according to some aspects.

FIG. 10 is a flow chart of another exemplary method for a UE to minimizeBLER associated with an expected beam switch according to some aspects.

FIG. 11 illustrates exemplary signaling between a UE and a base stationto minimize the BLER based on a beam switch according to some aspects.

FIG. 12 is a block diagram illustrating an example of a hardwareimplementation for a base station employing a processing systemaccording to some aspects.

FIG. 13 is a flow chart of an exemplary method for a base station tominimize BLER associated with a beam switch according to some aspects.

FIG. 14 is a flow chart of another exemplary method for a base stationto minimize BLER associated with a beam switch according to someaspects.

FIG. 15 is a flow chart of another exemplary method for a base stationto minimize BLER associated with a beam switch according to someaspects.

FIG. 16 is a flow chart of another exemplary method for a base stationto minimize BLER associated with a beam switch according to someaspects.

FIG. 17 is a flow chart of another exemplary method for a base stationto minimize BLER associated with a beam switch according to someaspects.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

While aspects and embodiments are described in this application byillustration to some examples, those skilled in the art will understandthat additional implementations and use cases may come about in manydifferent arrangements and scenarios. Innovations described herein maybe implemented across many differing platform types, devices, systems,shapes, sizes, packaging arrangements. For example, embodiments and/oruses may come about via integrated chip embodiments and othernon-module-component based devices (e.g., end-user devices, vehicles,communication devices, computing devices, industrial equipment,retail/purchasing devices, medical devices, AI-enabled devices, etc.).While some examples may or may not be specifically directed to use casesor applications, a wide assortment of applicability of describedinnovations may occur. Implementations may range a spectrum fromchip-level or modular components to non-modular, non-chip-levelimplementations and further to aggregate, distributed, or OEM devices orsystems incorporating one or more aspects of the described innovations.In some practical settings, devices incorporating described aspects andfeatures may also necessarily include additional components and featuresfor implementation and practice of claimed and described embodiments.For example, transmission and reception of wireless signals necessarilyincludes a number of components for analog and digital purposes (e.g.,hardware components including antenna, RF-chains, power amplifiers,modulators, buffer, processor(s), interleaver, adders/summers, etc.). Itis intended that innovations described herein may be practiced in a widevariety of devices, chip-level components, systems, distributedarrangements, end-user devices, etc. of varying sizes, shapes andconstitution.

The various concepts presented throughout this disclosure may beimplemented across a broad variety of telecommunication systems, networkarchitectures, and communication standards. Referring now to FIG. 1, asan illustrative example without limitation, various aspects of thepresent disclosure are illustrated with reference to a wirelesscommunication system 100. The wireless communication system 100 includesthree interacting domains: a core network 102, a radio access network(RAN) 104, and a user equipment (UE) 106. By virtue of the wirelesscommunication system 100, the UE 106 may be enabled to carry out datacommunication with an external data network 110, such as (but notlimited to) the Internet.

The RAN 104 may implement any suitable wireless communication technologyor technologies to provide radio access to the UE 106. As one example,the RAN 104 may operate according to 3rd Generation Partnership Project(3GPP) New Radio (NR) specifications, often referred to as 5G. Asanother example, the RAN 104 may operate under a hybrid of 5G NR andEvolved Universal Terrestrial Radio Access Network (eUTRAN) standards,often referred to as LTE. The 3GPP refers to this hybrid RAN as anext-generation RAN, or NG-RAN. Of course, many other examples may beutilized within the scope of the present disclosure.

As illustrated, the RAN 104 includes a plurality of base stations 108.Broadly, a base station is a network element in a radio access networkresponsible for radio transmission and reception in one or more cells toor from a UE. In different technologies, standards, or contexts, a basestation may variously be referred to by those skilled in the art as abase transceiver station (BTS), a radio base station, a radiotransceiver, a transceiver function, a basic service set (BSS), anextended service set (ESS), an access point (AP), a Node B (NB), aneNode B (eNB), a gNode B (gNB), or some other suitable terminology.

The radio access network 104 is further illustrated supporting wirelesscommunication for multiple mobile apparatuses. A mobile apparatus may bereferred to as user equipment (UE) in 3GPP standards, but may also bereferred to by those skilled in the art as a mobile station (MS), asubscriber station, a mobile unit, a subscriber unit, a wireless unit, aremote unit, a mobile device, a wireless device, a wirelesscommunications device, a remote device, a mobile subscriber station, anaccess terminal (AT), a mobile terminal, a wireless terminal, a remoteterminal, a handset, a terminal, a user agent, a mobile client, aclient, or some other suitable terminology. A UE may be an apparatusthat provides a user with access to network services.

Within the present document, a “mobile” apparatus need not necessarilyhave a capability to move, and may be stationary. The term mobileapparatus or mobile device broadly refers to a diverse array of devicesand technologies. UEs may include a number of hardware structuralcomponents sized, shaped, and arranged to help in communication; suchcomponents can include antennas, antenna arrays, RF chains, amplifiers,one or more processors, etc. electrically coupled to each other. Forexample, some non-limiting examples of a mobile apparatus include amobile, a cellular (cell) phone, a smart phone, a session initiationprotocol (SIP) phone, a laptop, a personal computer (PC), a notebook, anetbook, a smartbook, a tablet, a personal digital assistant (PDA), anda broad array of embedded systems, e.g., corresponding to an “Internetof Things” (IoT). A mobile apparatus may additionally be an automotiveor other transportation vehicle, a remote sensor or actuator, a robot orrobotics device, a satellite radio, a global positioning system (GPS)device, an object tracking device, a drone, a multi-copter, aquad-copter, a remote control device, a consumer and/or wearable device,such as eyewear, a wearable camera, a virtual reality device, a smartwatch, a health or fitness tracker, a digital audio player (e.g., MP3player), a camera, a game console, etc. A mobile apparatus mayadditionally be a digital home or smart home device such as a homeaudio, video, and/or multimedia device, an appliance, a vending machine,intelligent lighting, a home security system, a smart meter, etc. Amobile apparatus may additionally be a smart energy device, a securitydevice, a solar panel or solar array, a municipal infrastructure devicecontrolling electric power (e.g., a smart grid), lighting, water, etc.;an industrial automation and enterprise device; a logistics controller;agricultural equipment; military defense equipment, vehicles, aircraft,ships, and weaponry, etc. Still further, a mobile apparatus may providefor connected medicine or telemedicine support, i.e., health care at adistance. Telehealth devices may include telehealth monitoring devicesand telehealth administration devices, whose communication may be givenpreferential treatment or prioritized access over other types ofinformation, e.g., in terms of prioritized access for transport ofcritical service data, and/or relevant QoS for transport of criticalservice data.

Wireless communication between a RAN 104 and a UE 106 may be describedas utilizing an air interface. Transmissions over the air interface froma base station (e.g., base station 108) to one or more UEs (e.g., UE106) may be referred to as downlink (DL) transmission. In accordancewith certain aspects of the present disclosure, the term downlink mayrefer to a point-to-multipoint transmission originating at a schedulingentity (described further below; e.g., base station 108). Another way todescribe this scheme may be to use the term broadcast channelmultiplexing. Transmissions from a UE (e.g., UE 106) to a base station(e.g., base station 108) may be referred to as uplink (UL)transmissions. In accordance with further aspects of the presentdisclosure, the term uplink may refer to a point-to-point transmissionoriginating at a scheduled entity (described further below; e.g., UE106).

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station 108) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more scheduledentities. That is, for scheduled communication, UEs 106, which may bescheduled entities, may utilize resources allocated by the schedulingentity 108.

Base stations 108 are not the only entities that may function asscheduling entities. That is, in some examples, a UE may function as ascheduling entity, scheduling resources for one or more scheduledentities (e.g., one or more other UEs). And as discussed more below, UEsmay communicate directly with other UEs in peer-to-peer fashion and/orin relay configuration.

As illustrated in FIG. 1, a scheduling entity 108 may broadcast downlinktraffic 112 to one or more scheduled entities 106. Broadly, thescheduling entity 108 is a node or device responsible for schedulingtraffic in a wireless communication network, including the downlinktraffic 112 and, in some examples, uplink traffic 116 from one or morescheduled entities 106 to the scheduling entity 108. On the other hand,the scheduled entity 106 is a node or device that receives downlinkcontrol information 114, including but not limited to schedulinginformation (e.g., a grant), synchronization or timing information, orother control information from another entity in the wirelesscommunication network such as the scheduling entity 108.

In addition, the uplink and/or downlink control information and/ortraffic information may be time-divided into frames, subframes, slots,and/or symbols. As used herein, a symbol may refer to a unit of timethat, in an orthogonal frequency division multiplexed (OFDM) waveform,carries one resource element (RE) per sub-carrier. A slot may carry 7 or14 OFDM symbols. A subframe may refer to a duration of 1 ms. Multiplesubframes or slots may be grouped together to form a single frame orradio frame. Of course, these definitions are not required, and anysuitable scheme for organizing waveforms may be utilized, and varioustime divisions of the waveform may have any suitable duration.

In general, base stations 108 may include a backhaul interface forcommunication with a backhaul portion 120 of the wireless communicationsystem. The backhaul 120 may provide a link between a base station 108and the core network 102. Further, in some examples, a backhaul networkmay provide interconnection between the respective base stations 108.Various types of backhaul interfaces may be employed, such as a directphysical connection, a virtual network, or the like using any suitabletransport network.

The core network 102 may be a part of the wireless communication system100, and may be independent of the radio access technology used in theRAN 104. In some examples, the core network 102 may be configuredaccording to 5G standards (e.g., 5GC). In other examples, the corenetwork 102 may be configured according to a 4G evolved packet core(EPC), or any other suitable standard or configuration.

Referring now to FIG. 2, by way of example and without limitation, aschematic illustration of a RAN 200 is provided. In some examples, theRAN 200 may be the same as the RAN 104 described above and illustratedin FIG. 1. The geographic area covered by the RAN 200 may be dividedinto cellular regions (cells) that can be uniquely identified by a userequipment (UE) based on an identification broadcasted from one accesspoint or base station. FIG. 2 illustrates macrocells 202, 204, and 206,and a small cell 208, each of which may include one or more sectors (notshown). A sector is a sub-area of a cell. All sectors within one cellare served by the same base station. A radio link within a sector can beidentified by a single logical identification belonging to that sector.In a cell that is divided into sectors, the multiple sectors within acell can be formed by groups of antennas with each antenna responsiblefor communication with UEs in a portion of the cell.

Various base station arrangements can be utilized. For example, in FIG.2, two base stations 210 and 212 are shown in cells 202 and 204; and athird base station 214 is shown controlling a remote radio head (RRH)216 in cell 206. That is, a base station can have an integrated antennaor can be connected to an antenna or RRH by feeder cables. In theillustrated example, the cells 202, 204, and 126 may be referred to asmacrocells, as the base stations 210, 212, and 214 support cells havinga large size. Further, a base station 218 is shown in the small cell 208(e.g., a microcell, picocell, femtocell, home base station, home Node B,home eNode B, etc.) which may overlap with one or more macrocells. Inthis example, the cell 208 may be referred to as a small cell, as thebase station 218 supports a cell having a relatively small size. Cellsizing can be done according to system design as well as componentconstraints.

It is to be understood that the radio access network 200 may include anynumber of wireless base stations and cells. Further, a relay node may bedeployed to extend the size or coverage area of a given cell. The basestations 210, 212, 214, 218 provide wireless access points to a corenetwork for any number of mobile apparatuses. In some examples, the basestations 210, 212, 214, and/or 218 may be the same as the basestation/scheduling entity 108 described above and illustrated in FIG. 1.

Within the RAN 200, the cells may include UEs that may be incommunication with one or more sectors of each cell. Further, each basestation 210, 212, 214, and 218 may be configured to provide an accesspoint to a core network 102 (see FIG. 1) for all the UEs in therespective cells. For example, UEs 222 and 224 may be in communicationwith base station 210; UEs 226 and 228 may be in communication with basestation 212; UEs 230 and 232 may be in communication with base station214 by way of RRH 216; and UE 234 may be in communication with basestation 218. In some examples, the UEs 222, 224, 226, 228, 230, 232,234, 238, 240, and/or 242 may be the same as the UE/scheduled entity 106described above and illustrated in FIG. 1.

In some examples, an unmanned aerial vehicle (UAV) 220, which may be adrone or quadcopter, can be a mobile network node and may be configuredto function as a UE. For example, the UAV 220 may operate within cell202 by communicating with base station 210.

In a further aspect of the RAN 200, sidelink signals may be used betweenUEs without necessarily relying on scheduling or control informationfrom a base station. For example, two or more UEs (e.g., UEs 226 and228) may communicate with each other using peer to peer (P2P) orsidelink signals 227 without relaying that communication through a basestation (e.g., base station 212). In a further example, UE 238 isillustrated communicating with UEs 240 and 242. Here, the UE 238 mayfunction as a scheduling entity or a primary sidelink device, and UEs240 and 242 may each function as a scheduled entity or a non-primary(e.g., secondary) sidelink device. In still another example, a UE mayfunction as a scheduling entity or scheduled entity in adevice-to-device (D2D), peer-to-peer (P2P), vehicle-to-vehicle (V2V)network, vehicle-to-everything (V2X) and/or in a mesh network. In a meshnetwork example, UEs 240 and 242 may optionally communicate directlywith one another in addition to communicating with the scheduling entity238. Thus, in a wireless communication system with scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, or a mesh configuration, a scheduling entity and one ormore scheduled entities may communicate utilizing the scheduledresources. In some examples, the sidelink signals 227 include sidelinktraffic and sidelink control.

The air interface in the radio access network 200 may utilize one ormore multiplexing and multiple access algorithms to enable simultaneouscommunication of the various devices. For example, 5G NR specificationsprovide multiple access for UL transmissions from UEs 222 and 224 tobase station 210, and for multiplexing for DL transmissions from basestation 210 to one or more UEs 222 and 224, utilizing orthogonalfrequency division multiplexing (OFDM) with a cyclic prefix (CP). Inaddition, for UL transmissions, 5G NR specifications provide support fordiscrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (alsoreferred to as single-carrier I-DMA (SC-FDMA)). However, within thescope of the present disclosure, multiplexing and multiple access arenot limited to the above schemes, and may be provided utilizing timedivision multiple access (TDMA), code division multiple access (CDMA),frequency division multiple access (FDMA), sparse code multiple access(SCMA), resource spread multiple access (RSMA), or other suitablemultiple access schemes. Further, multiplexing DL transmissions from thebase station 210 to UEs 222 and 224 may be provided utilizing timedivision multiplexing (TDM), code division multiplexing (CDM), frequencydivision multiplexing (FDM), orthogonal frequency division multiplexing(OFDM), sparse code multiplexing (SCM), or other suitable multiplexingschemes.

The air interface in the radio access network 200 may further utilizeone or more duplexing algorithms. Duplex refers to a point-to-pointcommunication link where both endpoints can communicate with one anotherin both directions. Full duplex means both endpoints can simultaneouslycommunicate with one another. Half duplex means only one endpoint cansend information to the other at a time. In a wireless link, a fullduplex channel generally relies on physical isolation of a transmitterand receiver, and suitable interference cancellation technologies. Fullduplex emulation is frequently implemented for wireless links byutilizing frequency division duplex (FDD) or time division duplex (TDD).In FDD, transmissions in different directions operate at differentcarrier frequencies. In TDD, transmissions in different directions on agiven channel are separated from one another using time divisionmultiplexing. That is, at some times the channel is dedicated fortransmissions in one direction, while at other times the channel isdedicated for transmissions in the other direction, where the directionmay change very rapidly, e.g., several times per slot.

Various aspects of the present disclosure will be described withreference to an OFDM waveform, schematically illustrated in FIG. 3. Itshould be understood by those of ordinary skill in the art that thevarious aspects of the present disclosure may be applied to an SC-FDMAwaveform in substantially the same way as described herein below. Thatis, while some examples of the present disclosure may focus on an OFDMlink for clarity, it should be understood that the same principles maybe applied as well to SC-FDMA waveforms.

Referring now to FIG. 3, an expanded view of an exemplary DL subframe302 is illustrated, showing an OFDM resource grid. However, as thoseskilled in the art will readily appreciate, the PHY transmissionstructure for any particular application may vary from the exampledescribed here, depending on any number of factors. Here, time is in thehorizontal direction with units of OFDM symbols; and frequency is in thevertical direction with units of subcarriers.

The resource grid 304 may be used to schematically representtime-frequency resources for a given antenna port. That is, in amultiple-input-multiple-output (MIMO) implementation with multipleantenna ports available, a corresponding multiple number of resourcegrids 304 may be available for communication. The resource grid 304 isdivided into multiple resource elements (REs) 306. An RE, which is 1subcarrier×1 symbol, is the smallest discrete part of the time-frequencygrid, and contains a single complex value representing data from aphysical channel or signal. Depending on the modulation utilized in aparticular implementation, each RE may represent one or more bits ofinformation. In some examples, a block of REs may be referred to as aphysical resource block (PRB) or a resource block (RB) 308, whichcontains any suitable number of consecutive subcarriers in the frequencydomain. In one example, an RB may include 12 subcarriers, a numberindependent of the numerology used. In some examples, depending on thenumerology, an RB may include any suitable number of consecutive OFDMsymbols in the time domain. Within the present disclosure, it is assumedthat a single RB such as the RB 308 entirely corresponds to a singledirection of communication (either transmission or reception for a givendevice).

Scheduling of UEs (e.g., scheduled entities) for downlink or uplinktransmissions typically involves scheduling one or more resourceelements 306 within one or more sub-bands. Thus, a UE generally utilizesonly a subset of the resource grid 304. In some examples, an RB may bethe smallest unit of resources that can be allocated to a UE. Thus, themore RBs scheduled for a UE, and the higher the modulation scheme chosenfor the air interface, the higher the data rate for the UE.

In this illustration, the RB 308 is shown as occupying less than theentire bandwidth of the subframe 302, with some subcarriers illustratedabove and below the RB 308. In a given implementation, the subframe 302may have a bandwidth corresponding to any number of one or more RBs 308.Further, in this illustration, the RB 308 is shown as occupying lessthan the entire duration of the subframe 302, although this is merelyone possible example.

Each 1 ms subframe 302 may consist of one or multiple adjacent slots. Inthe example shown in FIG. 3, one subframe 302 includes four slots 310,as an illustrative example. In some examples, a slot may be definedaccording to a specified number of OFDM symbols with a given cyclicprefix (CP) length. For example, a slot may include 7 or 14 OFDM symbolswith a nominal CP. Additional examples may include mini-slots, sometimesreferred to as shortened transmission time intervals (TTIs), having ashorter duration (e.g., one to three OFDM symbols). These mini-slots orshortened transmission time intervals (TTIs) may in some cases betransmitted occupying resources scheduled for ongoing slot transmissionsfor the same or for different UEs. Any number of resource blocks may beutilized within a subframe or slot.

An expanded view of one of the slots 310 illustrates the slot 310including a control region 312 and a data region 314. In general, thecontrol region 312 may carry control channels, and the data region 314may carry data channels. Of course, a slot may contain all DL, all UL,or at least one DL portion and at least one UL portion. The structureillustrated in FIG. 3 is merely exemplary in nature, and different slotstructures may be utilized, and may include one or more of each of thecontrol region(s) and data region(s).

Although not illustrated in FIG. 3, the various REs 306 within a RB 308may be scheduled to carry one or more physical channels, includingcontrol channels, shared channels, data channels, etc. Other REs 306within the RB 308 may also carry pilots or reference signals, includingbut not limited to a demodulation reference signal (DMRS) a controlreference signal (CRS), or a sounding reference signal (SRS). Thesepilots or reference signals may provide for a receiving device toperform channel estimation of the corresponding channel, which mayenable coherent demodulation/detection of the control and/or datachannels within the RB 308.

In a DL transmission, the transmitting device (e.g., the schedulingentity 108) may allocate one or more REs 306 (e.g., within a controlregion 312) to carry DL control information including one or more DLcontrol channels, such as a PBCH; a PSS; a SSS; a physical controlformat indicator channel (PCFICH); a physical hybrid automatic repeatrequest (HARQ) indicator channel (PHICH); and/or a physical downlinkcontrol channel (PDCCH), etc., to one or more scheduled entities. ThePCFICH provides information to assist a receiving device in receivingand decoding the PDCCH. The PDCCH carries downlink control information(DCI) including but not limited to power control commands, schedulinginformation, a grant, and/or an assignment of REs for DL and ULtransmissions. The PHICH carries HARQ feedback transmissions such as anacknowledgment (ACK) or negative acknowledgment (NACK). HARQ is atechnique well-known to those of ordinary skill in the art, wherein theintegrity of packet transmissions may be checked at the receiving sidefor accuracy, e.g., utilizing any suitable integrity checking mechanism,such as a checksum or a cyclic redundancy check (CRC). If the integrityof the transmission confirmed, an ACK may be transmitted, whereas if notconfirmed, a NACK may be transmitted. In response to a NACK, thetransmitting device may send a HARQ retransmission, which may implementchase combining, incremental redundancy, etc.

In an UL transmission, the transmitting device (e.g., the scheduledentity 106) may utilize one or more REs 306 to carry UL controlinformation including one or more UL control channels, such as aphysical uplink control channel (PUCCH), to the scheduling entity. ULcontrol information may include a variety of packet types andcategories, including pilots, reference signals, and informationconfigured to enable or assist in decoding uplink data transmissions. Insome examples, the control information may include a scheduling request(SR), i.e., request for the scheduling entity to schedule uplinktransmissions. Here, in response to the SR transmitted on the controlchannel, the scheduling entity may transmit downlink control informationthat may schedule resources for uplink packet transmissions. UL controlinformation may also include HARQ feedback, channel state feedback(CSF), or any other suitable UL control information.

In addition to control information, one or more REs 306 (e.g., withinthe data region 314) may be allocated for user data traffic. Suchtraffic may be carried on one or more traffic channels, such as, for aDL transmission, a physical downlink shared channel (PDSCH); or for anUL transmission, a physical uplink shared channel (PUSCH). In someexamples, one or more REs 306 within the data region 314 may beconfigured to carry system information blocks (SIBs), carryinginformation that may enable access to a given cell.

These physical channels described above are generally multiplexed andmapped to transport channels for handling at the medium access control(MAC) layer. Transport channels carry blocks of information calledtransport blocks (TB). The transport block size (TBS), which maycorrespond to a number of bits of information, may be a controlledparameter, based on the modulation and coding scheme (MCS) and thenumber of RBs in a given transmission.

The channels or carriers described above in connection with FIGS. 1-3are not necessarily all of the channels or carriers that may be utilizedbetween a scheduling entity and scheduled entities, and those ofordinary skill in the art will recognize that other channels or carriersmay be utilized in addition to those illustrated, such as other traffic,control, and feedback channels.

In some aspects of the disclosure, the scheduling entity and/orscheduled entity may be configured for beamforming and/or multiple-inputmultiple-output (MIMO) technology. FIG. 4 illustrates an example of awireless communication system 400 supporting beamforming and/or MIMO. Ina MIMO system, a transmitter 402 includes multiple transmit antennas 404(e.g., N transmit antennas) and a receiver 406 includes multiple receiveantennas 408 (e.g., M receive antennas). Thus, there are N×M signalpaths 410 from the transmit antennas 404 to the receive antennas 408.Each of the transmitter 402 and the receiver 406 may be implemented, forexample, within a scheduling entity, a scheduled entity, or any othersuitable wireless communication device.

The use of such multiple antenna technology enables the wirelesscommunication system to exploit the spatial domain to support spatialmultiplexing, beamforming, and transmit diversity. Spatial multiplexingmay be used to transmit different streams of data, also referred to aslayers, simultaneously on the same time-frequency resource. The datastreams may be transmitted to a single UE to increase the data rate orto multiple UEs to increase the overall system capacity, the latterbeing referred to as multi-user MIMO (MU-MIMO). This is achieved byspatially precoding each data stream (i.e., multiplying the data streamswith different weighting and phase shifting) and then transmitting eachspatially precoded stream through multiple transmit antennas on thedownlink. The spatially precoded data streams arrive at the UE(s) withdifferent spatial signatures, which enables each of the UE(s) to recoverthe one or more data streams destined for that UE. On the uplink, eachUE transmits a spatially precoded data stream, which enables the basestation to identify the source of each spatially precoded data stream.

The number of data streams or layers corresponds to the rank of thetransmission. In general, the rank of the MIMO system 400 is limited bythe number of transmit or receive antennas 404 or 408, whichever islower. In addition, the channel conditions at the UE, as well as otherconsiderations, such as the available resources at the base station, mayalso affect the transmission rank. For example, the rank (and therefore,the number of data streams) assigned to a particular UE on the downlinkmay be determined based on the rank indicator (RI) transmitted from theUE to the base station. The RI may be determined based on the antennaconfiguration (e.g., the number of transmit and receive antennas) and ameasured signal-to-interference-and-noise ratio (SINR) on each of thereceive antennas. The RI may indicate, for example, the number of layersthat may be supported under the current channel conditions. The basestation may use the RI, along with resource information (e.g., theavailable resources and amount of data to be scheduled for the UE), toassign a transmission rank to the UE.

In one example, as shown in FIG. 4, a rank-2 spatial multiplexingtransmission on a 2×2 MIMO antenna configuration will transmit one datastream from each transmit antenna 404. Each data stream reaches eachreceive antenna 408 along a different signal path 410. The receiver 406may then reconstruct the data streams using the received signals fromeach receive antenna 408.

Beamforming is a signal processing technique that may be used at thetransmitter 402 or receiver 406 to shape or steer an antenna beam (e.g.,a transmit beam or receive beam) along a spatial path between thetransmitter 402 and the receiver 406. Beamforming may be achieved bycombining the signals communicated via antennas 404 or 408 (e.g.,antenna elements of an antenna array module) such that some of thesignals experience constructive interference while others experiencedestructive interference. To create the desired constructive/destructiveinterference, the transmitter 402 or receiver 406 may apply amplitudeand/or phase offsets to signals transmitted or received from each of theantennas 404 or 408 associated with the transmitter 402 or receiver 406.

A base station (e.g., gNB) may generally be capable of communicatingwith UEs using beams of varying beam widths. For example, a base stationmay be configured to utilize a wider beam when communicating with a UEthat is in motion and a narrower beam when communicating with a UE thatis stationary. In some examples, to select a particular beam forcommunication with a UE, the base station may transmit a referencesignal, such as a synchronization signal block (SSB) or channel stateinformation reference signal (CSI-RS), on each of a plurality of beamsin a beam-sweeping manner. The UE may measure the reference signalreceived power (RSRP) on each of the beams and transmit a beammeasurement report to the base station indicating the RSRP of each ofthe measured beams. The base station may then select the particular beamfor communication with the UE based on the beam measurement report. Inother examples, when the channel is reciprocal, the base station mayderive the particular beam to communicate with the UE based on uplinkmeasurements of one or more uplink reference signals, such as a soundingreference signal (SRS).

In 5G New Radio (NR) systems, particularly for above 6 GHz or mmWavesystems, beamformed signals may be utilized for most downlink channels,including the physical downlink control channel (PDCCH) and physicaldownlink shared channel (PDSCH). In addition, broadcast controlinformation, such as the master system information block (MSIB), slotformat indicator (SFI), and paging information, may be transmitted in abeam-sweeping manner to enable all scheduled entities (UEs) in thecoverage area of a transmission and reception point (TRP) (e.g., a gNB)to receive the broadcast control information. In addition, for UEsconfigured with beamforming antenna arrays, beamformed signals may alsobe utilized for uplink channels, including the physical uplink controlchannel (PUCCH) and physical uplink shared channel (PUSCH). However, itshould be understood that beamformed signals may also be utilized byenhanced mobile broadband (eMBB) gNBs for sub 6 GHz systems.

FIG. 5 is a diagram illustrating communication between a base station(BS) 504, such as a gNB, and a UE 502 using downlink beamformed signalsaccording to some aspects of the disclosure. The base station 504 may beany of the base stations or scheduling entities illustrated in FIGS. 1and 2, and the UE 502 may be any of the UEs or scheduled entitiesillustrated in FIGS. 1 and 2. It should be noted that while some beamsare illustrated as adjacent to one another, such an arrangement may bedifferent in different aspects. In some examples, beams transmittedduring a same symbol may not be adjacent to one another. In someexamples, the BS 504 may transmit more or less beams distributed in alldirections (e.g., 360 degrees).

In the example shown in FIG. 5, a beam set contains eight differentbeams 521, 522, 523, 524, 525, 526, 527, 528, each associated with adifferent beam direction. In some examples, the BS 504 may be configuredto sweep or transmit each of the beams 521, 522, 523, 524, 525, 526,527, 528 during a synchronization slot. For example, the BS 504 maytransmit a reference signal, such as an SSB or CSI-RS, on each beam inthe different beam directions during the synchronization slot.Transmission of the beam reference signals may occur periodically (e.g.,as configured via radio resource control (RRC) signaling by the gNB),semi-persistently (e.g., as configured via RRC signaling andactivated/deactivated via medium access control—control element (MAC-CE)signaling by the gNB), or aperiodically (e.g., as triggered by the gNBvia downlink control information (DCI)).

The UE 502 utilizes the received beam reference signals to identify thebeams and perform received power measurements (e.g., RSRP) on the beamreference signals. The UE 502 may then transmit a beam measurementreport 560 the respective beam index and RSRP of each beam 521-528. TheBS 504 may then determine the downlink beam (e.g., beam 524) on which totransmit unicast downlink control information and/or user data trafficto the UE 502 with the highest gain from the beam measurement report560. Transmission of the beam measurement report 560 may occurperiodically (e.g., as configured via RRC signaling by the gNB),semi-persistently (e.g., as configured via RRC signaling andactivated/deactivated via MAC-CE signaling by the gNB), or aperiodically(e.g., as triggered by the gNB via DCI).

In other examples, when the channel is reciprocal (e.g., the downlinkand uplink channel qualities are the same), the BS 504 may derive adownlink beam. Derivation can be based on the UE 502's uplinkmeasurements, such as by measuring the received power, quality, or othervariable of a sounding reference signal (SRS) or other uplink referencesignal. In some examples, a UE may not transmit a beam measurementreport 560 to the BS 504. In some examples, the BS 504 may select a pairof beams (e.g., a downlink transmit beam associated with the BS 504 anda downlink reception beam associated with the UE 502) as a beam pairlink (BPL) based on the received beam measurement report 560 and/oruplink measurements.

When the BS 504 switches from one downlink beam to another downlinkbeam, the BS 504 may perform link adaptation. Link adaptation can adjusta modulation and coding scheme (MCS). Adjustment may occur with respectto a link budget associated with a new downlink beam. In some examples,the BS 504 may utilize an outer-loop link adaptation process in whichthe MCS may be modified based on the HARQ feedback (e.g., ACKs andNACKs) from the UE 502. In other examples, the BS 504 may dynamicallyschedule the transmission of a CSI-RS to the UE 502 on the new downlinkbeam. From the CSI-RS, the UE 502 may measure the channel quality andprovide channel state feedback (CSF) to the BS 504. The CSF may include,for example, a channel quality indicator (CQI) from which the BS 504 mayselect/adjust the MCS utilized for unicast transmissions to the UE 502on the new downlink beam. Upon selecting/adjusting the MCS, the BS 504may then further utilize an outer-loop link adaptation process tofurther modify the MCS, as needed, until another CSI-RS is transmittedto the UE 502.

Although the dynamic transmission of the CSI-RS to the UE 502 may resultin a faster MCS adjustment than the outer-loop link adaptation process,in either scenario, the beam switch is followed by a link adaptationconvergence period in which the link may suffer from a block error rate(BLER) burst when moving to a beam with a lower spectral efficiency orthe link may suffer from lower throughput when moving to a beam withhigher spectral efficiency.

Moreover, when the beams are quasi-co-located (or QCL'd), the BS 504 maynot signal to the UE 502 that the BS 504 is switching beams. This mayresult in the UE 502 experiencing a sudden increase in received signalstrength, which may increase the BLER at the UE 502. For example, whenthe BS 504 switches from a wide beam to a narrow beam, the antenna gaindifference between the wide beam and the narrow beam may be significant,resulting a large received signal strength jump at the UE 502.

In various aspects of the disclosure, to minimize the BLER afterperforming a downlink beam switch from a current downlink beam to a newdownlink beam, the BS 504 may mitigate the link adaptation convergenceperiod. Mitigation can occur by adjusting the MCS according a differencein RSRP between a current beam and a new beam. In some examples, thedifference in RSRP may be discerned from the beam measurement report 560sent from the UE 502 to the BS 504. In other examples, channelreciprocity may be leveraged, where the BS 504 may derive the differencein RSRP from uplink measurements on corresponding uplink beamsassociated with the BS 504. For example, the BS 504 may compare theuplink channel quality (e.g., received power) measured on a previousuplink beam corresponding to the previous downlink beam at the BS 504prior to the beam switch with the uplink channel quality (e.g., receivedpower) measured on a new uplink beam corresponding to the new downlinkbeam at the BS 504 after the beam switch.

By adjusting the MCS based on the difference in RSRP, an initial changein the MCS may be applied in a first slot after the beam switch, whichreduces the convergence time for outer-loop link adaptation. Inaddition, the BLER during the convergence period may be reduced whenmoving to a beam with a lower RSRP. In examples in which CSF is used forlink adaptation, performing an initial adjustment to the MCS based onthe difference in RSRP optimizes the link adaptation until the first CSFis reported by the UE 502.

In other aspects of the disclosure, to minimize the BLER at the UE 502upon a downlink beam switch, the UE 502 may modify an automatic gaincontrol (AGC) state of the UE. Modification can be based on thedifference in RSRP between a current downlink beam and an expecteddownlink beam. In some example, an expected downlink beam may be a beamthat expected to be selected by the BS 504 for subsequent downlinktransmissions to the UE 502 (e.g., unicast transmissions). The UE 502may identify the expected downlink beam based on RSRP measurements madeby the UE 502 during the synchronization slot (e.g., during a beamsweep). In some examples, the expected downlink beam may have a highestRSRP among all of the measured RSRPs of the different downlink beams. Inother examples, the expected downlink beam may have a lower RSRP or begrouped into a range of desired RSRP levels. Expected downlink beams maybe selected based on a variety of criteria (e.g., power, timing, signalquality, channel conditions, beam type, polarization, operatingconditions, etc.). The UE 502 may further apply a slow attenuation tothe AGC state to converge back to the nominal value of the currentdownlink beam in circumstances in which the BS 504 does not switchbeams.

By modifying the AGC state prior to beam switch based on an expecteddownlink beam, the AGC step response latency may be reduced to near zeroand the AGC may be in an optimal state in the first slot after the beamswitch. As a result, the BLER experienced by the UE may be minimizedwhen switching from a wide beam to a narrow beam or, more generally,from a beam with lower RSRP to a beam with higher RSRP.

FIG. 6 illustrates an example of a UE 600 configured to modify an AGCstate of one or more receiver gain stages within the UE. The UE 600includes an antenna 602, a low noise amplifier (LNA) 604, adown-conversion module 606, a local oscillator 608, an optional variablegain amplifier 610, an analog-to-digital converter (ADC) 612, and aprocessor 614. The antenna 602 may be a single antenna that is shared bytransmit and receive paths (half-duplex) or may include separateantennas for the transmit path and receive path (full-duplex). Theantenna may further include multiple transmit and/or receive antennas tosupport MIMO and/or beamforming technology.

The LNA 604 is configured to receive a radio frequency (RF) signal fromthe antenna 602 and to amplify the RF signal to produce an amplified RFsignal. The down-conversion module 606 is configured to receive theamplified RF signal from the LNA 604 and to convert the amplified RFsignal into a low intermediate frequency (IF) signal or baseband signalbased on a local oscillation provided by the local oscillator 608. Theoptional VGA 610 is configured to receive the low IF or baseband signalfrom the down-conversion module and to adjust the gain of the low IF orbaseband signal before providing the low IF or baseband signal to theADC 612. The ADC 612 converts the low IF or baseband signal from theanalog domain to the digital domain to produce a digital signal that maybe processed by the processor 614. For example, the processor 614 maydemodulate, demap, descramble, and/or decode the digital signal toproduce information (e.g., control information and/or user datatraffic).

The UE 600 further includes an additional ADC 616 and an automatic gaincontrol (AGC) module 618. The additional ADC 616 is configured toreceive the low IF signal or baseband signal from the down-conversionmodule and to convert the low IF signal or baseband signal from theanalog domain to the digital domain to produce an additional digitalsignal for input to the AGC module 618. The AGC module 618 is configuredto continuously monitor the received power (or received signal strength)of the additional digital signal and adjust one or more receiver gainstages of the UE based on the received power (or received signalstrength) to ensure the received signal strength at the input to the ADC612 is sufficient for proper decoding. The one or more gain stages mayinclude, for example, the LNA 604 and the VGA 610.

For example, if the received strength is low, the AGC module 618 mayboost the one or more receiver gain stages. Doing so can minimize noiseand bring the signal level to an acceptable signal-to-noise ratio (SNR)at the input to the ADC 612 (e.g., within the dynamic range of the ADC612). As another example, if the received signal strength is high, theAGC module 618 may attenuate the one or more receiver gain stages toavoid signal clipping and nonlinear degradation and bring the signallevel to an acceptable SNR at the input to the ADC 612. In general, theAGC module 618 may be configured to increase or decrease the gain of theone or more gain stages by a specific step size based on a comparisonbetween the received signal strength and one or more thresholds, each ofwhich may be associated with a different gain step size. For example,the gain step sizes per threshold may be defined in a look-up table (notshown).

In various aspects of the disclosure, the processor 614 may further beconfigured to instruct the AGC module 618 to modify the AGC state of oneor more of the receiver gain stages (e.g., LNA 604 and/or VGA 610).Modification can be based on a difference in the RSRP of a currentdownlink beam currently utilized by a base station for communicationwith the UE 600 and an expected downlink beam expected to be utilized bythe base station for a subsequent downlink transmission to the UE 600.In some examples, the processor 614 may instruct the AGC module 618 tomodify the AGC state by an amount equal to the difference between theRSRP of the current beam and the RSRP of the expected beam.

In an example, the processor 614 can carry out and/or implement a numberof specialized actions or functions. For example, the processor 614 maybe configured to receive a respective reference signal on each of aplurality of downlink beams Receipt of reference signals may be during abeam sweep performed by the base station (e.g., via the antenna 602, LNA604, down-conversion module 606, VGA 610, and ADC 612). As anotherexample, the processor 614 may measure the RSRP of the respectivereference signal corresponding to each of the plurality of downlinkbeams. The processor 614 may further be configured to compare themeasured RSRP of each the downlink beams to identify the expecteddownlink beam expected to be utilized by the base station for thesubsequent downlink transmission. In some examples, the expecteddownlink beam has the highest measured RSRP among all of the measuredRSRPs of the downlink beams. The processor 614 may further identify themeasured RSRP of the current downlink beam and calculate the differencebetween the measured RSRP of the current downlink beam and the measuredRSRP of the expected downlink beam. Based on the RSRP difference, theprocessor 614 may then instruct the AGC module 618 to modify the AGCstate by an amount corresponding to the RSRP difference.

FIG. 7 illustrates exemplary signaling between a UE 702 and a basestation 704 to minimize the BLER based on an expected beam switch. TheUE 702 may correspond to any of the UEs shown in FIGS. 1, 2, 5, and/or6. In addition, the base station 704 may correspond to any of the basestations shown in FIGS. 1, 2, 5, and/or 6.

At 706, the base station 704 may perform a beam sweep to transmit areference signal (e.g., an SSB or CSI-RS) on each of a plurality ofdownlink beams to the UE 702. At 708, the UE 702 may measure the RSRP oneach of the plurality of downlink beams. At 710, the UE 702 may generateand transmit a beam measurement report including the measured RSRP ofeach of the plurality of downlink beams.

Based on the measured RSRP of each of the plurality of downlink beams,at 712, the UE 702 may further adjust the AGC state of the UE based onan expected beam of the plurality of beams expected to be selected bythe base station 704 for a subsequent unicast downlink transmission tothe UE 702. For example, the UE 702 may adjust the AGC state of one ormore receiver gain stages (e.g., the LNA and/or VGA in the receiverchain). In some examples, the UE 702 may modify the AGC state by anamount equal to the difference between the RSRP of a current downlinkbeam and the RSRP of the expected downlink beam. For example, when theUE 702 anticipates the base station 704 switching from a current widebeam to an expected narrow beam, the UE 702 may attenuate the one ormore receiver gain stages as a result of the expected increase in RSRPbetween the current wide beam and the expected narrow beam.

At 714, the UE 702 may receive a unicast downlink transmission via theexpected downlink beam from the base station 704. By modifying the AGCstate prior to receipt of the unicast downlink transmission, the UE 702may minimize the BLER of the unicast downlink transmission.

FIG. 8 is a conceptual diagram illustrating an example of a hardwareimplementation for an exemplary user equipment (UE) employing aprocessing system 814. For example, the UE 800 may be a UE asillustrated in any one or more of FIGS. 1, 2, and/or 5-7.

The UE 800 may be implemented with a processing system 814 that includesone or more processors 804. Examples of processors 804 includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. In various examples, the UE 800may be configured to perform any one or more of the functions describedherein. That is, the processor 804, as utilized in a UE 800, may be usedto implement any one or more of the processes described below. Theprocessor 804 may in some instances be implemented via a baseband ormodem chip and in other implementations, the processor 804 may itselfcomprise a number of devices distinct and different from a baseband ormodem chip (e.g., in such scenarios is may work in concert to achieveembodiments discussed herein). And as mentioned above, various hardwarearrangements and components outside of a baseband modem processor can beused in implementations, including RF-chains, power amplifiers,modulators, buffers, interleavers, adders/summers, etc.

In this example, the processing system 814 may be implemented with a busarchitecture, represented generally by the bus 802. The bus 802 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 814 and the overall designconstraints. The bus 802 communicatively couples together variouscircuits including one or more processors (represented generally by theprocessor 804), a memory 805, and computer-readable media (representedgenerally by the computer-readable medium 806). The bus 802 may alsolink various other circuits such as timing sources, peripherals, voltageregulators, and power management circuits, which are well known in theart, and therefore, will not be described any further. A bus interface808 provides an interface between the bus 802 and a transceiver 810. Thetransceiver 810 provides a means for communicating with various otherapparatus over a transmission medium (e.g., air interface). A userinterface 812 (e.g., keypad, display, speaker, microphone, joystick) mayalso be provided.

The processor 804 is responsible for managing the bus 802 and generalprocessing, including the execution of software stored on thecomputer-readable medium 806. The software, when executed by theprocessor 804, causes the processing system 814 to perform the variousfunctions described below for any particular apparatus. Thecomputer-readable medium 806 and the memory 805 may also be used forstoring data that is manipulated by the processor 804 when executingsoftware.

One or more processors 804 in the processing system may executesoftware.

Software shall be construed broadly to mean instructions, instructionsets, code, code segments, program code, programs, subprograms, softwaremodules, applications, software applications, software packages,routines, subroutines, objects, executables, threads of execution,procedures, functions, etc., whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise. Thesoftware may reside on a computer-readable medium 806.

The computer-readable medium 806 may be a non-transitorycomputer-readable medium. A non-transitory computer-readable mediumincludes, by way of example, a magnetic storage device (e.g., hard disk,floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD)or a digital versatile disc (DVD)), a smart card, a flash memory device(e.g., a card, a stick, or a key drive), a random access memory (RAM), aread only memory (ROM), a programmable ROM (PROM), an erasable PROM(EPROM), an electrically erasable PROM (EEPROM), a register, a removabledisk, and any other suitable medium for storing software and/orinstructions that may be accessed and read by a computer. Thecomputer-readable medium may also include, by way of example, a carrierwave, a transmission line, and any other suitable medium fortransmitting software and/or instructions that may be accessed and readby a computer. The computer-readable medium 806 may reside in theprocessing system 814, external to the processing system 814, ordistributed across multiple entities including the processing system814. The computer-readable medium 806 may be embodied in a computerprogram product. In some examples, the computer-readable medium 806 maybe part of the memory 805. By way of example, a computer program productmay include a computer-readable medium in packaging materials. Thoseskilled in the art will recognize how best to implement the describedfunctionality presented throughout this disclosure depending on theparticular application and the overall design constraints imposed on theoverall system.

In some aspects of the disclosure, the processor 804 may includecircuitry configured for various functions. For example, the processor804 may include communication and processing circuitry 842, configuredto communicate with a base station. In some examples, the communicationand processing circuitry 842 may include one or more hardware componentsthat provide the physical structure that performs processes related towireless communication (e.g., signal reception and/or signaltransmission) and signal processing (e.g., processing a received signaland/or processing a signal for transmission).

In some examples, the communication and processing circuitry 842 may beconfigured to generate and transmit an uplink beamformed signal at ammWave frequency or a sub-6 GHz frequency via the transceiver 810 andantenna array 820. For example, the communication and processingcircuitry 842 may be configured to transmit a beam measurement report815 to the base station. In addition, the communication and processingcircuitry 842 may be configured to receive and process a downlinkbeamformed signal at a mmWave frequency or a sub-6 GHz frequency via theantenna array module 820 and the transceiver 810. For example, thecommunication and processing circuitry 842 may be configured to receivea respective reference signal on each of a plurality of downlink beamsfrom the base station during a beam sweep. The communication andprocessing circuitry 842 may further be configured to receive unicastdownlink control information and/or user data traffic from the basestation on a selected downlink beam.

The communication and processing circuitry 842 may further be configuredto receive a CSI-RS from the base station on a current downlink beam andto transmit channel state feedback (CSF) to the base station in responseto the CSI-RS. The CSF may include, for example, a channel qualityindicator (CQI), precoding matrix indicator (PMI) and rank indicator(RI). In addition, the communication and processing circuitry 842 may beconfigured to implement a HARQ-based feedback mechanism to transmitACK/NACK to the base station. The communication and processing circuitry842 may further be configured to execute communication and processingsoftware 852 stored in the computer-readable medium 806 to implement oneor more of the functions described herein.

The processor 804 may further include beam management circuitry 844,configured to measure a respective RSRP on each of the plurality ofdownlink beams during the downlink beam sweep by the base station and togenerate the beam measurement report 815 for transmission to the basestation including the measured RSRP of each of the plurality of downlinkbeams. The beam measurement report 815 may further be stored within thememory 805 for further processing. In addition, the beam managementcircuitry 844 may be configured to identify an expected downlink beamexpected to be utilized by the base station for a subsequent downlinktransmission based on the respective RSRP measured for each of theplurality of downlink beams. In some examples, the expected downlinkbeam corresponds to the downlink beam having the highest measured RSRP.

The beam management circuitry 844 may further be configured to generateand transmit a variety of signals. The generation and transmission maybe done in conjunction with the communication and processing circuitry842. The reference signals can include an uplink reference signal oneach of a plurality of uplink beams in different beam directions. Eachuplink reference signal may include, for example, a contention-basedRACH (Random Access Channel) message or a Sounding Reference Signal(SRS). Transmission of a contention-based RACH message may occur duringinitial access and/or failure recovery utilizing RACH resources coveringall directions that are periodically allocated by the base station andshared by all UEs in the cell. Transmission of a SRS may occur duringconnected mode and may be aperiodically triggered by the base station,periodically scheduled by the base station, or semi-persistentlyscheduled by the base station. The base station may perform receivedbeam quality measurements on the uplink beam reference signals toidentify the uplink beam on which the UE should transmit controlinformation and/or user data traffic to the base station. Examples ofbeam quality measurements may include, but are not limited to, thereceived power or the signal-to-noise ratio (SNR). In some examples, thebeam management circuitry 844, together with the communication andprocessing circuitry 842, may receive an uplink beam selection signalindicating the selected serving uplink beam from the base station. Thebeam management circuitry 844 may further be configured to execute beammanagement software 854 stored in the computer-readable medium 806 toimplement one or more of the functions described herein.

The processor 804 may further include antenna gain control (AGC)circuitry 846 and received signal strength indicator (RSSI) measurementcircuitry 848. The AGC circuitry 846 may be configured to modify an AGCstate of the UE 800 based on the expected downlink beam identified bythe beam management circuitry 844. For example, the AGC circuitry 846may be configured to determine a first RSRP of the current downlink beammeasured by the beam management circuitry 844 and a second RSRP of theexpected downlink beam measured by the beam management circuitry 844.The AGC circuitry 846 may further be configured to modify the AGC stateof the UE 800 by an amount equal to the difference between the firstRSRP and the second RSRP. In some examples, the AGC circuitry 846 may beconfigured to attenuate one or more receiver gain stages (e.g., withinthe transceiver 810) by the amount equal to the difference between thefirst and second RSRPs. In some examples, the AGC circuitry 846 maycorrespond to the AGC module 618 and processor 614 shown in FIG. 6 andmay be configured to modify the AGC state of a LNA and/or VGA, asdescribed above in connection with FIG. 6.

The AGC circuitry 846 may further be configured to adjust the AGC stateover a period of time to converge back to an initial AGC state (e.g.,the nominal value associated with the current downlink beam prior tomodifying the AGC state for the expected downlink beam) when theexpected downlink beam is not selected by the base station forsubsequent unicast downlink transmissions to the UE 800. For example,the AGC circuitry 846 may apply a slow attenuation to the AGC state tosubstantially preserve the AGC state during the transition by the basestation from the current downlink beam to the expected downlink beam. Insome examples, the expected transition time interval for transitioningfrom the current downlink beam to the expected downlink beam may includeseveral slots. The AGC circuitry 846 may further apply slow attenuationto the AGC state over an additional time interval extending beyond theexpected transition time interval to converge the AGC state back to theinitial AGC state. Thus, the period of time over which the AGC circuitry846 may adjust (e.g., slowly attenuate) the AGC state may include boththe transition time interval and the additional time interval. The AGCcircuitry 846 may further be configured to execute AGC software 856stored in the computer-readable medium 806 to implement one or more ofthe functions described herein.

The RSSI measurement circuitry 848 may be configured to measure arespective RSSI of each of a plurality of received signals received fromthe base station over the period of time. The RSSI measurement circuitry848 may further be configured to provide the measured RSSI over theperiod of time to the AGC circuitry 846. The AGC circuitry 846 mayadjust (e.g., slowly attenuate) the AGC state when the measured RSSIsubstantially corresponds to the first RSRP of the current downlink beam(or similarly, the measured RSSI does not substantially correspond tothe second RSRP of the expected downlink beam), thus indicating that thebase station has not yet switched to the expected downlink beam. TheRSSI measurement circuitry 848 may further be configured to execute RSSImeasurement software 858 stored in the computer-readable medium 806 toimplement one or more of the functions described herein.

FIG. 9 is a flow chart 900 of a method for a UE to minimize BLERassociated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the UE 800, as describedabove and illustrated in FIG. 8, by a processor or processing system, orby any suitable means for carrying out the described functions.

At block 902, the UE may receive a plurality of downlink beams from abase station. For example, the base station may transmit a referencesignal on each of the plurality of downlink beams during a beam sweep tothe UE. For example, the communication and processing circuitry 842shown and described above in connection with FIG. 8 may receive theplurality of downlink beams.

At block 904, the UE may measure the respective RSRP of each of theplurality of downlink beams. For example, the beam management circuitry844 shown and described above in connection with FIG. 8 may measure theRSRP of each of the downlink beams.

At block 906, the UE may identify an expected downlink beam of theplurality of downlink beams expected to be utilized by the base stationfor a subsequent downlink transmission based on the measured RSRP ofeach of the plurality of downlink beams. In some examples, the expecteddownlink beam has the highest measured RSRP among all of the downlinkbeams. For example, the beam management circuitry 844 shown anddescribed above in connection with FIG. 8 may identify the expecteddownlink beam.

At block 908, the UE may modify an AGC state of the UE based on theexpected downlink beam prior to receipt of the subsequent downlinktransmission. In some examples, the UE may determine a first RSRP of thecurrent downlink beam currently utilized by the base station fordownlink transmissions and a second RSRP of the expected downlink beamexpected to be utilized by the base station for future downlinktransmissions. The UE may then modify the AGC state by an amount equalto the difference between the first RSRP and the second RSRP. In someexamples, the UE may be configured to attenuate one or more receivergain stages by the amount equal to the difference between the first andsecond RSRPs. For example, the AGC circuitry 846 shown and describedabove in connection with FIG. 8 may modify the AGC state of the UE.

FIG. 10 is a flow chart 1900 of a method for a UE to minimize BLERassociated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the UE 800, as describedabove and illustrated in FIG. 8, by a processor or processing system, orby any suitable means for carrying out the described functions.

At block 1002, the UE may receive a plurality of downlink beams from abase station. For example, the base station may transmit a referencesignal on each of the plurality of downlink beams during a beam sweep tothe UE. For example, the communication and processing circuitry 842shown and described above in connection with FIG. 8 may receive theplurality of downlink beams.

At block 1004, the UE may measure the respective RSRP of each of theplurality of downlink beams. For example, the beam management circuitry844 shown and described above in connection with FIG. 8 may measure theRSRP of each of the downlink beams.

At block 1006, the UE may identify an expected downlink beam of theplurality of downlink beams expected to be utilized by the base stationfor a subsequent downlink transmission based on the measured RSRP ofeach of the plurality of downlink beams. In some examples, the expecteddownlink beam has the highest measured RSRP among all of the downlinkbeams. For example, the beam management circuitry 844 shown anddescribed above in connection with FIG. 8 may identify the expecteddownlink beam.

At block 1008, the UE may modify an AGC state of the UE based on theexpected downlink beam prior to receipt of the subsequent downlinktransmission. In some examples, the UE may determine a first RSRP of thecurrent downlink beam currently utilized by the base station fordownlink transmissions and a second RSRP of the expected downlink beamexpected to be utilized by the base station for future downlinktransmissions. The UE may then modify the AGC state by an amount equalto the difference between the first RSRP and the second RSRP. In someexamples, the UE may be configured to attenuate one or more receivergain stages by the amount equal to the difference between the first andsecond RSRPs. For example, the AGC circuitry 846 shown and describedabove in connection with FIG. 8 may modify the AGC state of the UE.

At block 1010, the UE may measure the received signal strength (e.g.,the RSSI) of signals received from the base station. For example, theRSSI measurement circuitry 848 shown and described above in connectionwith FIG. 8 may measure the RSSI of received signals.

At block 1012, the UE may determine whether the measured RSSI is equalto the RSRP of the current downlink beam (e.g., as determined at block1004). If the measured RSSI is equal to the RSRP of the current downlinkbeam, at block 1014, the UE may adjust the AGC state to converge backtowards an initial AGC state (e.g., the nominal value prior to modifyingthe AGC state for the expected downlink beam). In some examples, the UEmay apply a slow attenuation to the AGC state to substantially preservethe modified AGC state during an expected transition time interval fortransitioning from the current downlink beam to the expected downlinkbeam. For example, the AGC circuitry 846 shown and described above inconnection with FIG. 8 may compare the measured RSSI to the measuredRSRP for the current downlink beam and adjust the AGC state when theRSSI is equal to the RSRP for the current downlink beam.

At block 1016, the UE may determine whether the AGC state has convergedback to the initial AGC state. If the AGC state differs from the initialAGC state, the process may return to block 1010, where the UE maymeasure the RSSI of received signals and further adjust the AGC state atblocks 1012 and 1014. For example, the AGC circuitry 846 shown anddescribed above in connection with FIG. 8 may determine whether the AGChas converged back to the initial AGC state.

FIG. 11 illustrates exemplary signaling between a UE 1102 and a basestation 1104 to minimize the BLER based on a beam switch. The UE 1102may correspond to any of the UEs shown in FIGS. 1, 2, and/or 5-8. Inaddition, the base station 1104 may correspond to any of the basestations shown in FIGS. 1, 2, and/or 5-7.

At 1106, the base station 1104 may perform a beam sweep to transmit areference signal (e.g., an SSB or CSI-RS) on each of a plurality ofdownlink beams to the UE 1102. At 1108, the UE 1102 may measure the RSRPon each of the plurality of downlink beams. At 1110, the UE 1102 maygenerate and transmit a beam measurement report including the measuredRSRP of each of the plurality of downlink beams to the base station1104.

At 1112, the base station 1104 may switch beams. An example switch caninclude switching from a first beam of the plurality of beams currentlyutilized for unicast downlink transmissions to the UE 1102 to a secondbeam of the plurality of beams for subsequent (future) unicast downlinktransmissions to the UE 1102 based on the measured RSRPs of the firstand second beams. For example, the second beam may have a higher RSRPthan the first beam. In some examples, the second beam may have thehighest RSRP among all of the beams.

At 1114, the base station 1104 may modify the modulation and codingscheme (MCS) based on the RSRP difference between the first and secondbeams. More particularly, the base station 1104 may modify the MCS forthe second beam based on the current MCS utilized for the first beam andthe RSRP difference between the first and second beams Generally,higher-order modulations (e.g., 64 QAM) may be utilized on beams with ahigher RSRP. In addition, for a given modulation scheme, an appropriatecode rate may be selected based on the channel (beam) quality. Forexample, a higher code rate may be utilized on beams with better quality(e.g., a higher RSRP). At 1116, the base station 1104 may generate aunicast downlink transmission towards the UE 1102 using the second beamand the modified (new) MCS.

FIG. 12 is a conceptual diagram illustrating an example of a hardwareimplementation for an exemplary base station 1200 employing a processingsystem 1214. For example, the base station 1200 may be a base station asillustrated in any one or more of FIGS. 1, 2, 5-7 and/or 11.

The processing system 1214 may be substantially the same as theprocessing system 814 illustrated in FIG. 8. The system 1214 can includea bus interface 1208, a bus 1202, memory 1205, a processor 1204, and acomputer-readable medium 1206. Furthermore, the base station 1200 mayinclude an optional user interface 1212 and a transceiver 1210substantially similar to those described above in FIG. 8. In addition,the UE may further include one or more antenna array modules 1220. Inaccordance with various aspects of the disclosure, an element, or anyportion of an element, or any combination of elements may be implementedwith the processing system 1214 that includes one or more processors1204. That is, the processor 1204, as utilized in a base station 1200,may be used to implement any one or more of the processes describedbelow.

In some aspects of the disclosure, the processor 1204 may includecircuitry configured for various functions. For example, the processor1204 may include resource assignment and scheduling circuitry 1242,configured to generate, schedule, and modify a resource assignment orgrant of time-frequency resources (e.g., a set of one or more resourceelements). For example, the resource assignment and scheduling circuitry1242 may schedule time-frequency resources within a plurality of timedivision duplex (TDD) and/or frequency division duplex (FDD) subframes,slots, and/or mini-slots to carry user data traffic and/or controlinformation to and/or from multiple UEs.

In some examples, the resource assignment and scheduling circuitry 1242may be configured to allocate/schedule downlink resources (e.g., mmWaveor sub-6 GHz resources) for the transmission of downlink beam referencesignals during a downlink beam sweep to a UE. The resource assignmentand scheduling circuitry 1242 may further be configured toallocate/schedule uplink resources for the transmission of a beammeasurement report from the UE to the base station 1200. In otherexamples, the resource assignment and scheduling circuitry 1242 may beconfigured to allocate/schedule uplink resources for the transmission ofuplink beam reference signals from the UE to the base station 1200during an uplink beam sweep. The resource assignment and schedulingcircuitry 1242 may further be configured to execute resource assignmentand scheduling software 1252 stored in the computer-readable medium 1206to implement one or more of the functions described herein.

The processor 1204 may further include communication and processingcircuitry 1244 configured to communicate with a UE. In some examples,the communication and processing circuitry 1244 may include one or morehardware components that provide the physical structure that performsprocesses related to wireless communication (e.g., signal receptionand/or signal transmission) and signal processing (e.g., processing areceived signal and/or processing a signal for transmission). In someexamples, the communication and processing circuitry 1244 may beconfigured to generate and transmit a downlink signal at a mmWavefrequency or a sub-6 GHz frequency via the transceiver 1210 and antennaarray module(s) 1220. In addition, the communication and processingcircuitry 1244 may be configured to receive and process an uplink signalat a mmWave frequency or a sub-6 GHz frequency via the antenna arraymodule(s) 1220 and the transceiver 1210.

For example, the communication and processing circuitry 1244 may beconfigured to generate and transmit a respective reference signal (e.g.,an SSB or CSI-RS) on each of a plurality of downlink beams to the UEduring a beam sweep. In addition, the communication and processingcircuitry 1244 may be configured to receive a beam measurement reportfrom the UE including the measured RSRP on each of the plurality ofdownlink beams. The communication and processing circuitry 1244 mayfurther be configured to receive a respective uplink reference signal(e.g., a RACH message or SRS) on each of a plurality of uplink beamsfrom the UE.

The communication and processing circuitry 1244 may further beconfigured to transmit a CSI-RS to the UE and receive channel statefeedback (CSF) 1218 from the UE in response to the CSI-RS. The CSF mayinclude, for example, a channel quality indicator (CQI), precodingmatrix indicator (PMI) and rank indicator (RI). In some examples, thecommunication and processing circuitry 1244 may store the CSF 1218 inmemory 1205 for further processing. In addition, the communication andprocessing circuitry 1244 may be configured to implement a HARQ feedbackmechanism to receive ACK/NACK from the UE. The communication andprocessing circuitry 1244 may further be configured to executecommunication and processing software 1254 stored on thecomputer-readable medium 1206 to implement one or more functionsdescribed herein.

The processor 1204 may further include beam management circuitry 1246,configured to communicate with a UE (e.g., in conjunction with thecommunication and processing circuitry 1244). Communication may utilizea first downlink beam of the plurality of downlink beams. The beammanagement circuitry 1246 may further be configured to process a beammeasurement report 1215 received from the UE (e.g., via thecommunication and processing circuitry 1244). The beam measurementreport (BMR) 1215 may include the measured RSRP of each of the pluralityof downlink beams. In addition, the BMR 1215 may further be storedwithin the memory 1205 for further processing. The beam managementcircuitry 1246 may be configured to switch from the first downlink beamto a second downlink beam of the plurality of downlink beams forcommunication with the UE based on the respective RSRP measured for eachof the plurality of downlink beams. For example, the second downlinkbeam may have a higher RSRP than the first downlink beam. In someexamples, the second downlink beam corresponds to the downlink beamhaving the highest measured RSRP. The beam management circuitry 1246 mayfurther be configured to calculate a difference between a first measuredRSRP associated with the first downlink beam and a second measured RSRPassociated with the second downlink beam from the beam measurementreport 1215.

The beam management circuitry 1246 may further be configured to receive(e.g., in conjunction with the communication and processing circuitry1244) a respective uplink reference signal on each of a plurality ofuplink beams from the UE. The beam management circuitry 1246 may furtherbe configured to perform signal quality measurements on the uplink beamreference signals to identify the uplink beam on which the UE shouldtransmit control information and/or user data traffic to the basestation 1200. Examples of signal quality measurements may include, butare not limited to, the received power or the signal-to-noise ratio(SNR). In examples in which the channel is reciprocal, the beammanagement circuitry 1246, may switch from the first downlink beam tothe second downlink beam based on the signal quality measurements ofcorresponding uplink beams. In this example, the beam managementcircuitry 1246 may estimate the difference between the first RSRP of thefirst downlink beam and the second RSRP of the second downlink beambased on the respective signal quality measurements of a first uplinkbeam corresponding to the first downlink beam and a second uplink beamcorresponding to the second downlink beam. The beam management circuitry1246 may further be configured to execute beam management software 1256stored in the computer-readable medium 1206 to implement one or more ofthe functions described herein.

The processor 1204 may further include MCS selection circuitry 1248,configured to select an MCS for unicast downlink transmissions to theUE. In some examples, the MCS selection circuitry 1248 may select an MCSfor downlink transmissions to the UE utilizing the first beam and thenmodify the MCS for downlink transmissions to the UE utilizing the secondbeam based on the difference between the first RSRP (associated with thefirst beam) and the second RSRP (associated with the second beam)determined by the beam management circuitry 1246. The MCS selectioncircuitry 1248 may modify the MCS utilized for downlink transmissions tothe UE on the second beam prior to transmitting unicast downlink controlinformation and/or user data traffic to the UE on the second beam. Insome examples, a different MCS may be utilized for control informationand user data traffic. The MCS selection circuitry 1248 may further beconfigured to execute MCS selection software 1258 stored in thecomputer-readable medium 1206 to implement one or more of the functionsdescribed herein.

The processor 1204 may further include link adaptation circuitry 1250,configured to further adjust the MCS after selecting the MCS for thesecond beam based on the RSRP difference between the first and secondbeams. In some examples, the link adaptation circuitry 1250 may utilizean outer-loop link adaptation process to adjust the MCS. For example,the link adaptation circuitry 1250 may be configured to adjust the MCSbased on acknowledgement information (e.g., ACKs and NACKs) receivedfrom the UE. In other examples, the link adaptation circuitry 1250 mayutilize the CSF 1218 received from the UE in response to a CSI-RStransmitted by the base station 1200 on the second beam to adjust theMCS. For example, the link adaptation circuitry 1250 may adjust the MCSbased on the CQI in the CSF 1218. Upon adjusting the MCS based on theCQI, the link adaptation circuitry 1250 may further utilize theouter-loop link adaptation process to further adjust the MCS, as needed,until another CSI-RS is transmitted to the UE on the second beam. Thelink adaptation circuitry 1250 may further be configured to execute linkadaptation software 1260 stored in the computer-readable medium 1206 toimplement one or more of the functions described herein.

FIG. 13 is a flow chart 1300 of a method for a base station to minimizeBLER associated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the base station 1200, asdescribed above and illustrated in FIG. 12, by a processor or processingsystem, or by any suitable means for carrying out the describedfunctions.

At block 1302, the base station may communicate with a UE utilizing afirst downlink beam of a plurality of downlink beams. The downlink beamsmay be, for example, mmWave or sub-6 GHz beams. For example, thecommunication and processing circuitry 1244 and beam managementcircuitry 1246 shown and described above in connection with FIG. 12 maycommunicate with the UE utilizing a first downlink beam.

At block 1304, the base station may switch from the first downlink beamto a second downlink beam of the plurality of downlink beams tocommunicate with the UE. In some examples, the base station may switchto the second downlink beam based on a difference between a first RSRPassociated with the first downlink beam and a second RSRP associatedwith the second downlink beam. For example, the base station maycalculate the RSRP difference based on a beam measurement reportincluding the first RSRP associated with the first downlink beam and thesecond RSRP associated with the second downlink beam. As anotherexample, the base station may estimate the RSRP difference between thefirst and second downlink beams based on uplink signal qualitymeasurements of corresponding first and second uplink beams. Forexample, the beam management circuitry 1246 shown and described above inconnection with FIG. 12 may determine the RSRP difference between thefirst and second downlink beams and switch to the second downlink beambased on the RSRP difference.

At block 1306, the base station may modify an MCS utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP. The modified MCS may be utilized for communicationwith the UE on the second beam immediately after switching from thefirst beam to the second beam (e.g., in the first slot after switching).For example, the MCS selection circuitry 1248 shown and described abovein connection with FIG. 12 may modify the MCS.

FIG. 14 is a flow chart 1400 of a method for a base station to minimizeBLER associated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the base station 1200, asdescribed above and illustrated in FIG. 12, by a processor or processingsystem, or by any suitable means for carrying out the describedfunctions.

At block 1402, the base station may communicate with a UE utilizing afirst downlink beam of a plurality of downlink beams. The downlink beamsmay be, for example, mmWave or sub-6 GHz beams. For example, thecommunication and processing circuitry 1244 and beam managementcircuitry 1246 shown and described above in connection with FIG. 12 maycommunicate with the UE utilizing a first downlink beam.

At block 1404, the base station may receive a beam measurement reportfrom the UE. The beam measurement report may include a respective RSRPmeasured on each of a plurality of downlink beams during a beam sweepperformed by the base station. In particular, the beam measurementreport may include a first RSRP of the first beam and a second RSRP of asecond beam, where the second RSRP may be higher than the first RSRP. Insome examples, the second RSRP may be a highest RSRP among all of thedownlink beams. For example, the beam management circuitry 1246 andcommunication and processing circuitry 1244 shown and described above inconnection with FIG. 12 may receive the beam measurement report.

At block 1406, the base station may switch from the first downlink beamto a second downlink beam of the plurality of downlink beams tocommunicate with the UE based on a difference between the first RSRPassociated with the first downlink beam and the second RSRP associatedwith the second downlink beam. For example, the beam managementcircuitry 1246 shown and described above in connection with FIG. 12 maydetermine the RSRP difference between the first and second downlinkbeams and switch to the second downlink beam based on the RSRPdifference.

At block 1408, the base station may modify an MCS utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP. The modified MCS may be utilized for communicationwith the UE on the second beam immediately after switching from thefirst beam to the second beam (e.g., in the first slot after switching).For example, the MCS selection circuitry 1248 shown and described abovein connection with FIG. 12 may modify the MCS.

FIG. 15 is a flow chart 1500 of a method for a base station to minimizeBLER associated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the base station 1200, asdescribed above and illustrated in FIG. 12, by a processor or processingsystem, or by any suitable means for carrying out the describedfunctions.

At block 1502, the base station may communicate with a UE utilizing afirst downlink beam of a plurality of downlink beams. The downlink beamsmay be, for example, mmWave or sub-6 GHz beams. For example, thecommunication and processing circuitry 1244 and beam managementcircuitry 1246 shown and described above in connection with FIG. 12 maycommunicate with the UE utilizing a first downlink beam.

At block 1504, when the channel is reciprocal, the base station mayestimate a difference between a first RSRP associated with the firstdownlink beam and a second RSRP associated with a second downlink beamof the plurality of downlink beams based on respective uplink signalquality measurements of a first uplink beam corresponding to the firstdownlink beam and a second uplink beam corresponding to the seconddownlink beam. For example, the beam management circuitry 1246 shown anddescribed above in connection with FIG. 12 may estimate the RSRPdifference.

At block 1506, the base station may switch from the first downlink beamto the second downlink beam of the plurality of downlink beams.Switching may enable the BS to communicate with the UE based on theestimated difference between the first RSRP associated with the firstdownlink beam and the second RSRP associated with the second downlinkbeam. For example, the beam management circuitry 1246 shown anddescribed above in connection with FIG. 12 may switch to the seconddownlink beam based on the RSRP difference.

At block 1508, the base station may modify an MCS utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP. The modified MCS may be utilized for communicationwith the UE on the second beam immediately after switching from thefirst beam to the second beam (e.g., in the first slot after switching).For example, the MCS selection circuitry 1248 shown and described abovein connection with FIG. 12 may modify the MCS.

FIG. 16 is a flow chart 1600 of a method for a base station to minimizeBLER associated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the base station 1200, asdescribed above and illustrated in FIG. 12, by a processor or processingsystem, or by any suitable means for carrying out the describedfunctions.

At block 1602, the base station may communicate with a UE utilizing afirst downlink beam of a plurality of downlink beams. The downlink beamsmay be, for example, mmWave or sub-6 GHz beams. For example, thecommunication and processing circuitry 1244 and beam managementcircuitry 1246 shown and described above in connection with FIG. 12 maycommunicate with the UE utilizing a first downlink beam.

At block 1604, the base station may switch from the first downlink beamto a second downlink beam of the plurality of downlink beams tocommunicate with the UE. In some examples, the base station may switchto the second downlink beam based on a difference between a first RSRPassociated with the first downlink beam and a second RSRP associatedwith the second downlink beam. For example, the base station maycalculate the RSRP difference based on a beam measurement reportincluding the first RSRP associated with the first downlink beam and thesecond RSRP associated with the second downlink beam. As anotherexample, the base station may estimate the RSRP difference between thefirst and second downlink beams based on uplink signal qualitymeasurements of corresponding first and second uplink beams. Forexample, the beam management circuitry 1246 shown and described above inconnection with FIG. 12 may determine the RSRP difference between thefirst and second downlink beams and switch to the second downlink beambased on the RSRP difference.

At block 1606, the base station may modify an MCS utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP. The modified MCS may be utilized for communicationwith the UE on the second beam immediately after switching from thefirst beam to the second beam (e.g., in the first slot after switching).For example, the MCS selection circuitry 1248 shown and described abovein connection with FIG. 12 may modify the MCS.

At block 1608, the base station may further adjust the MCS utilizing anouter-loop link adaptation process. For example, the base station may beconfigured to adjust the MCS based on the HARQ feedback (e.g., ACKs andNACKs) received from the UE. For example, the link adaptation circuitry1250 shown and described above in connection with FIG. 12 may furtheradjust the MCS after modifying the MCS based on the RSRP difference.

FIG. 17 is a flow chart 1700 of a method for a base station to minimizeBLER associated with a beam switch. As described below, some or allillustrated features may be omitted in a particular implementationwithin the scope of the present disclosure, and some illustratedfeatures may not be required for implementation of all embodiments. Insome examples, the method may be performed by the base station 1200, asdescribed above and illustrated in FIG. 12, by a processor or processingsystem, or by any suitable means for carrying out the describedfunctions.

At block 1702, the base station may communicate with a UE utilizing afirst downlink beam of a plurality of downlink beams. The downlink beamsmay be, for example, mmWave or sub-6 GHz beams. For example, thecommunication and processing circuitry 1244 and beam managementcircuitry 1246 shown and described above in connection with FIG. 12 maycommunicate with the UE utilizing a first downlink beam.

At block 1704, the base station may switch from the first downlink beamto a second downlink beam of the plurality of downlink beams tocommunicate with the UE. In some examples, the base station may switchto the second downlink beam based on a difference between a first RSRPassociated with the first downlink beam and a second RSRP associatedwith the second downlink beam. For example, the base station maycalculate the RSRP difference based on a beam measurement reportincluding the first RSRP associated with the first downlink beam and thesecond RSRP associated with the second downlink beam. As anotherexample, the base station may estimate the RSRP difference between thefirst and second downlink beams based on uplink signal qualitymeasurements of corresponding first and second uplink beams. Forexample, the beam management circuitry 1246 shown and described above inconnection with FIG. 12 may determine the RSRP difference between thefirst and second downlink beams and switch to the second downlink beambased on the RSRP difference.

At block 1706, the base station may modify an MCS utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP. The modified MCS may be utilized for communicationwith the UE on the second beam immediately after switching from thefirst beam to the second beam (e.g., in the first slot after switching).For example, the MCS selection circuitry 1248 shown and described abovein connection with FIG. 12 may modify the MCS.

At block 1708, the base station may transmit a CSI-RS to the UE via thesecond downlink beam. For example, the communication and processingcircuitry 1244, together with the transceiver 1210, shown and describedabove in connection with FIG. 12 may transmit the CSI-RS to the UE onthe second beam.

At block 1710, the base station may receive CSF from the UE based on theCSI-RS. For example, the communication and processing circuitry 1244,together with the transceiver 1210, shown and described above inconnection with FIG. 12 may receive the CSF.

At block 1712, the base station may further adjust the MCS based on theCSF. For example, the base station may be configured to adjust the MCSbased on the CQI included in the CSF. For example, the link adaptationcircuitry 1250 shown and described above in connection with FIG. 12 mayfurther adjust the MCS after modifying the MCS based on the RSRPdifference.

In one configuration, a base station includes means for communicatingwith a user equipment (UE) utilizing a first downlink beam of aplurality of downlink beams, means for switching from the first downlinkbeam to a second downlink beam of the plurality of downlink beams tocommunicate with the UE based on a difference between a first referencesignal received power (RSRP) associated with the first downlink beam anda second RSRP associated with the second downlink beam, and means formodifying a modulation and coding scheme (MCS) utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP.

In one aspect, the aforementioned means for communicating with a userequipment (UE) utilizing a first downlink beam of a plurality ofdownlink beams, means for switching from the first downlink beam to asecond downlink beam of the plurality of downlink beams to communicatewith the UE based on a difference between a first reference signalreceived power (RSRP) associated with the first downlink beam and asecond RSRP associated with the second downlink beam, and means formodifying a modulation and coding scheme (MCS) utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP may be the processor(s) 1204 shown in FIG. 12configured to perform the functions recited by the aforementioned means.For example, the aforementioned means for communicating with a userequipment (UE) utilizing a first downlink beam of a plurality ofdownlink beams may include the communication and processing circuitry1244, beam management circuitry 1246, transceiver 1210, and antennaarray 1220 shown in FIG. 12. As another example, the aforementionedmeans for switching from the first downlink beam to a second downlinkbeam of the plurality of downlink beams to communicate with the UE basedon a difference between a first reference signal received power (RSRP)associated with the first downlink beam and a second RSRP associatedwith the second downlink beam may include the beam management circuitry1246 shown in FIG. 12. In another example, the aforementioned means formodifying a modulation and coding scheme (MCS) utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP may include the MCS selection circuitry 1248 andlink adaptation circuitry 1250 shown in FIG. 12. In another aspect, theaforementioned means may be a circuit or any apparatus configured toperform the functions recited by the aforementioned means.

Several aspects of a wireless communication network have been presentedwith reference to an exemplary implementation. As those skilled in theart will readily appreciate, various aspects described throughout thisdisclosure may be extended to other telecommunication systems, networkarchitectures and communication standards.

By way of example, various aspects may be implemented within othersystems defined by 3GPP, such as Long-Term Evolution (LTE), the EvolvedPacket System (EPS), the Universal Mobile Telecommunication System(UMTS), and/or the Global System for Mobile (GSM). Various aspects mayalso be extended to systems defined by the 3rd Generation PartnershipProject 2 (3GPP2), such as CDMA2000 and/or Evolution-Data Optimized(EV-DO). Other examples may be implemented within systems employing IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB),Bluetooth, and/or other suitable systems. The actual telecommunicationstandard, network architecture, and/or communication standard employedwill depend on the specific application and the overall designconstraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean“serving as an example, instance, or illustration.” Any implementationor aspect described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other aspects of thedisclosure. Likewise, the term “aspects” does not require that allaspects of the disclosure include the discussed feature, advantage ormode of operation. The term “coupled” is used herein to refer to thedirect or indirect coupling between two objects. For example, if objectA physically touches object B, and object B touches object C, thenobjects A and C may still be considered coupled to one another—even ifthey do not directly physically touch each other. For instance, a firstobject may be coupled to a second object even though the first object isnever directly physically in contact with the second object. The terms“circuit” and “circuitry” are used broadly, and intended to include bothhardware implementations of electrical devices and conductors that, whenconnected and configured, enable the performance of the functionsdescribed in the present disclosure, without limitation as to the typeof electronic circuits, as well as software implementations ofinformation and instructions that, when executed by a processor, enablethe performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functionsillustrated in FIGS. 1-17 may be rearranged and/or combined into asingle component, step, feature or function or embodied in severalcomponents, steps, or functions. Additional elements, components, steps,and/or functions may also be added without departing from novel featuresdisclosed herein. The apparatus, devices, and/or components illustratedin FIGS. 1, 2, 4-8, 11, and 12 may be configured to perform one or moreof the methods, features, or steps described herein. The novelalgorithms described herein may also be efficiently implemented insoftware and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of exemplary processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample orderand are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but are to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a,b, and c. All structural and functional equivalents to the elements ofthe various aspects described throughout this disclosure that are knownor later come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims.

What is claimed is:
 1. A method for wireless communication at a basestation in a wireless communication network, the method comprising:communicating with a user equipment (UE) utilizing a first downlink beamof a plurality of downlink beams; switching from the first downlink beamto a second downlink beam of the plurality of downlink beams tocommunicate with the UE based on a difference between a first referencesignal received power (RSRP) associated with the first downlink beam anda second RSRP associated with the second downlink beam; modifying amodulation and coding scheme (MCS) utilized for communication with theUE based on the difference between the first RSRP and the second RSRP;and reducing, based on the modified MCS, a link adaptation convergenceperiod in which: a block error rate (BLER) burst occurs when the secondRSRP is higher than the first RSRP; and a reduction in throughput occurswhen the second RSRP is lower than the first RSRP.
 2. The method ofclaim 1, further comprising: receiving at least one beam measurementreport from the UE, wherein the first RSRP and the second RSRP are eachincluded in one of the at least one beam measurement report; andcalculating the difference between the first RSRP and the second RSRPbased on the at least one beam measurement report.
 3. The method ofclaim 1, further comprising: estimating the difference between the firstRSRP and the second RSRP based on respective signal quality measurementsof a first uplink beam corresponding to the first downlink beam and asecond uplink beam corresponding to the second downlink beam.
 4. Themethod of claim 1, wherein modifying the MCS further comprises:adjusting the MCS utilizing an outer-loop link adaptation process. 5.The method of claim 4, further comprising: receiving acknowledgementinformation from the UE; and adjusting the MCS based on theacknowledgement information.
 6. The method of claim 1, wherein modifyingthe MCS further comprises: transmitting a channel stateinformation—reference signal (CSI-RS) to the UE via the second beam;receiving channel state information feedback (CSF) from the UE; andadjusting the MCS based on the CSF.
 7. The method of claim 1, whereinthe first downlink beam comprises a first beam width and the seconddownlink beam comprises a second beam width, wherein the second beamwidth is different than the first beam width.
 8. The method of claim 1,wherein communicating with the UE further comprises: communicating withthe UE utilizing a millimeter wave carrier frequency.
 9. A base stationfor wireless communication network, comprising: a wireless transceiver;a memory; and a processor coupled to the wireless transceiver and thememory, wherein the processor is configured to: communicate with a userequipment (UE) utilizing a first downlink beam of a plurality ofdownlink beams via the wireless transceiver; switch from the firstdownlink beam to a second downlink beam of the plurality of downlinkbeams to communicate with the UE based on a difference between a firstreference signal received power (RSRP) associated with the firstdownlink beam and a second RSRP associated with the second downlinkbeam; modify a modulation and coding scheme (MCS) utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP; and reduce, based on the modified MCS, a linkadaptation convergence period in which: a block error rate (BLER) burstoccurs when the second RSRP is higher than the first RSRP; and areduction in throughput occurs when the second RSRP is lower than thefirst RSRP.
 10. The base station of claim 9, wherein the processor isfurther configured to: receive at least one beam measurement report fromthe UE via the wireless transceiver, wherein the first RSRP and thesecond RSRP are each included in one of the at least one beammeasurement report; and calculate the difference between the first RSRPand the second RSRP based on the at least one beam measurement report.11. The base station of claim 9, wherein the processor is furtherconfigured to: estimate the difference between the first RSRP and thesecond RSRP based on respective signal quality measurements of a firstuplink beam corresponding to the first downlink beam and a second uplinkbeam corresponding to the second downlink beam.
 12. The base station ofclaim 9, wherein the processor is further configured to: adjust the MCSutilizing an outer-loop link adaptation process.
 13. The base station ofclaim 12, wherein the processor is further configured to: receiveacknowledgement information from the UE; and adjust the MCS based on theacknowledgement information.
 14. The base station of claim 9, whereinthe processor is further configured to: transmit a channel stateinformation—reference signal (CSI-RS) to the UE via the second beam;receive channel state information feedback (CSF) from the UE; and adjustthe MCS based on the CSF.
 15. The base station of claim 9, wherein thefirst downlink beam comprises a first beam width and the second downlinkbeam comprises a second beam width, wherein the second beam width isdifferent than the first beam width.
 16. The base station of claim 9,wherein the processor is further configured to: communicate with the UEutilizing a millimeter wave carrier frequency via the wirelesstransceiver.
 17. A base station for wireless communication, comprising:means for communicating with a user equipment (UE) utilizing a firstdownlink beam of a plurality of downlink beams; means for switching fromthe first downlink beam to a second downlink beam of the plurality ofdownlink beams to communicate with the UE based on a difference betweena first reference signal received power (RSRP) associated with the firstdownlink beam and a second RSRP associated with the second downlinkbeam; means for modifying a modulation and coding scheme (MCS) utilizedfor communication with the UE based on the difference between the firstRSRP and the second RSRP; and means for reducing, based on the modifiedMCS, a link adaptation convergence period in which: a block error rate(BLER) burst occurs when the second RSRP is higher than the first RSRP;and a reduction in throughput occurs when the second RSRP is lower thanthe first RSRP.
 18. The base station of claim 17, further comprising:means for receiving at least one beam measurement report from the UE,wherein the first RSRP and the second RSRP are each included in one ofthe at least one beam measurement report; and means for calculating thedifference between the first RSRP and the second RSRP based on the atleast one beam measurement report.
 19. The base station of claim 17,further comprising: means for estimating the difference between thefirst RSRP and the second RSRP based on respective signal qualitymeasurements of a first uplink beam corresponding to the first downlinkbeam and a second uplink beam corresponding to the second downlink beam.20. The base station of claim 17, wherein the means for modifying theMCS further comprises: means for adjusting the MCS utilizing anouter-loop link adaptation process.
 21. The base station of claim 20,wherein the means for modifying the MCS further comprises: means forreceiving acknowledgement information from the UE; and means foradjusting the MCS based on the acknowledgement information.
 22. The basestation of claim 17, wherein the means for modifying the MCS furthercomprises: means for transmitting a channel state information —referencesignal (CSI-RS) to the UE via the second beam; means for receivingchannel state information feedback (CSF) from the UE; and means foradjusting the MCS based on the CSF.
 23. The base station of claim 17,wherein the first downlink beam comprises a first beam width and thesecond downlink beam comprises a second beam width, wherein the secondbeam width is different than the first beam width.
 24. The base stationof claim 17, wherein the means for communicating with the UE furthercomprises: means for communicating with the UE utilizing a millimeterwave carrier frequency.
 25. A non-transitory computer-readable mediumstoring computer-executable code, comprising code for causing a basestation to: communicate with a user equipment (UE) utilizing a firstdownlink beam of a plurality of downlink beams; switch from the firstdownlink beam to a second downlink beam of the plurality of downlinkbeams to communicate with the UE based on a difference between a firstreference signal received power (RSRP) associated with the firstdownlink beam and a second RSRP associated with the second downlinkbeam; modify a modulation and coding scheme (MCS) utilized forcommunication with the UE based on the difference between the first RSRPand the second RSRP; and reduce, based on the modified MCS, a linkadaptation convergence period in which: a block error rate (BLER) burstoccurs when the second RSRP is higher than the first RSRP; and areduction in throughput occurs when the second RSRP is lower than thefirst RSRP.
 26. The non-transitory computer-readable medium of claim 25,further comprising code for causing the base station to: receive atleast one beam measurement report from the UE, wherein the first RSRPand the second RSRP are each included in one of the at least one beammeasurement report; and calculate the difference between the first RSRPand the second RSRP based on the at least one beam measurement report.27. The non-transitory computer-readable medium of claim 25, furthercomprising code for causing the base station to: estimate the differencebetween the first RSRP and the second RSRP based on respective signalquality measurements of a first uplink beam corresponding to the firstdownlink beam and a second uplink beam corresponding to the seconddownlink beam.
 28. The non-transitory computer-readable medium of claim26, further comprising code for causing the base station to: adjust theMCS utilizing an outer-loop link adaptation process.
 29. Thenon-transitory computer-readable medium of claim 28, further comprisingcode for causing the base station to: receive acknowledgementinformation from the UE; and adjust the MCS based on the acknowledgementinformation.
 30. The non-transitory computer-readable medium of claim25, further comprising code for causing the base station to: transmit achannel state information —reference signal (CSI-RS) to the UE via thesecond beam; receive channel state information feedback (CSF) from theUE; and adjust the MCS based on the CSF.